Some consumers are believed to show a preference for thickened cleaning or brightening compositions and thickened cleaners are useful, for example, as oven cleaners, paint strippers and toilet bowl cleaners as they can be more readily positioned upon the area being cleaned. Additives for thickeners have included natural gums such as guar and locust bean extract, starches and cellulose and their derivatives.
Polymeric thickeners for acidic surfactant compositions are described by U.S. Pat. No. 4,552,685, issued Nov. 12, 1985, inventors Kernstock et al. and by U.S. Pat. No. 4,529,773, issued Jul. 16, 1985, inventors Witiak et al. However, these acidic-thickened solutions require high levels of surfactant in order to solubilize the copolymers and they have higher viscosities at pH 7 than when the pH is lowered into the acidic region.